Conversion of cinema theatre to a super cinema theatre

ABSTRACT

Methods of and equipment for converting existing standard motion picture theatres to one having highly immersive, large fields of view are addressed. Aspects of the methods including moving motion picture screens closer to the audience and employing different projection equipment to avoid or minimize appearance of unrealistic or non-natural image artifacts. Alternative sound systems too are detailed.

This application is a continuation of U.S. patent application Ser. No.11/494,686 filed Jul. 27, 2006, now pending, which application is acontinuation of U.S. patent application Ser. No. 10/839,665, filed May5, 2004, now U.S. Pat. No. 7,106,411, having the same title as appearsabove, the entire contents of both of which applications are herebyincorporated herein by this reference.

FIELD OF THE INVENTION

The field of the invention is the presentation of motion picture films,and in particular in the cost effective conversion of a standard,existing multiplex theatre space into one allowing a qualitativelydifferent motion picture presentation experience.

BACKGROUND

Motion picture exhibition has seen a number of changes since itsinception in the late 19^(th) century. Generally, the main variables inmotion picture exhibition have been the dimensions of the theatreenclosure and correspondingly the number of seats therein, the size ofthe screen upon which images were projected and the dimensions or formatof the film negative which contained the images for presentation.Although a number of film formats were considered, one format, 35 mmwide film having an image aspect ratio of 4:3 became the industrystandard. Motion picture theatres gradually evolved in size from smallertheatres to larger so-called palace theatres featuring several hundredto thousands of seats, balconies, and elaborate facades. Despite theimpressive and somewhat regal atmosphere these theatres continued tofeature 35 mm film projected onto narrow width screen. Eventually in thelate 1920s, motion picture producers and exhibitors startedexperimenting with larger film formats which could enhance the visualimmersion of theatre patrons and live up to the size and scope of thelarge palace theatres.

Some of the wide gauge/wide screen processes that appeared to challengethe 35 mm film standard included Magnascope, Polyvision, Hypergonar andFox Grandeur. Magnascope used a novel magnifying lens to enlarge astandard 35 mm frame. Polyvision used multiple 35 mm film projectors tostitch together a composite image, while Fox Grandeur replaced 35 mmfilm entirely with a new 70 mm wide film format. Finally Hypergonar useda novel method of anamorphically squeezing images onto a 35 mm frameduring filming and then reversing the process upon projection to fill alarger projection screen.

Although technically and aesthetically successful, the proposed widescreen systems failed to replace 35 mm as a film standard in theeconomically depressed 1930s and were soon abandoned. Conditions hadchanged somewhat by the early 1950s and the motion picture industry sawa resurgence of proposals for wide gauge/wide screen systems. Foremostamong the new systems were Cinerama, a multiple 35 mm projection system,Cinemascope, an anamorphic system, Vistavision a 35 mm 8 perforationformat system and Todd AO, a wide gauge system using a 70 mm 5perforation 30 frame per second format. The new formats were successfulat the box office and survived for a number of years, but none was ableto seriously challenge the 35 mm film standard.

A third wave of wide gauge/wide screen motion picture exhibition startedin 1969, led by IMAX Corporation, which featured the use of horizontallytravelling 70 mm film with a film frame of 15 perforations in widthresulting in an image area about ten times that of standard 35 mm. Inaddition to the large film format IMAX® re-conceptualized the theatreviewing space by providing significantly larger screens which extendedbeyond spectators fields of view, steeply raked seating area to giveunobstructed viewing of said large screen, and high fidelity six channelsound to surround the audience. The net result of these advances was atheatre experience in which audience members were immersed in image andsound as never before. IMAX® theatres were successful in theinstitutional and exhibit marketplace. Other competing large formatsystems include Showscan's 70 mm 5 perforation film projected at 60frames per second (versus the standard 24 fps) and Iwerk's 70 mm 5, 8and 15 perforation film systems.

In most cases IMAX® systems were installed in custom designed motionpicture theatres having a large volume to house both the large screenand a steeply raked seating deck. Occasionally IMAX® projection systemswere placed in large hall converted stage theatres. IMAX® screens couldbe placed in front of the stages in such theatrical structures withoutbuilding structure modifications because of the large existing clearheight. In some cases, such as at the Museum of Natural History in NewYork City, a retractable IMAX® screen was placed in front of the stagethat had an existing 35 mm screen at the back of the stage. Some seatsat the side of the theatre near the position of the IMAX® screen wereremoved because the visual quality at those locations was poor. Theslope of the seating areas in these theatrical theatres is typicallyshallow, and financial constraints prevented conversion to a moredesirable steeper slope. As a result, the viewing conditions in suchconverted theatres were not optimized for viewing IMAX® motion pictures.

Grand theatres of the type frequented in the 1920s thru 1950s weresometimes converted to house the emerging wide gauge/widescreen systemsof the 1950s. Conversion consisted of changing the width and curvatureof the screen to match the new wider picture aspect ratio and removing arelatively high percentage of seats that no longer had viable viewingconditions. Screen centres were basically positioned at the originalscreen centre position at the rear wall of the theatre, and the rake ofseats in the theatres was not a consideration in the conversion process.

Another type of theatre conversion addresses the desire to presentmotion pictures in either of two common aspect ratio formats, which are1:85:1 and 2.35:1. The conversion process involves adjusting the curtainmasking around the screen to suit the format of presentation as well aschanging the lens and aperture plate. The position of the screen itselfdoes not change.

A major trend in the motion picture industry starting in the 1970s wasto group a number of small 35 mm film theatres into one large complex,or so-called multiplex theatre. These theatres, although profitable, didnot provide patrons with a quality viewing experience. Over time movieattendance declined partly because of new home entertainmenttechnologies such as cable TV, video cassette recorders, and home movierentals. In the 1990s the motion picture exhibition industry respondedto declining movie attendance by building new theatres offering stadiumseating—placing each row of seats on its own tier—to improve the sightlines and thus the viewing experience of patrons. This industry advancehas been very successful in improving movie attendance and is now anexpected feature for theatre patrons; conventional low slope seatingdecks are seen as “old” and inferior. (LA Business Journal). The newstadium seat theatres, while an improvement over traditional multiplextheatres, still rely on standard 35 mm film projectors and do notprovide patrons with a wide field of view or highly immersiveexperience.

It should be noted that in the later half of the 1990s the use ofdigital projectors began in a few multiplex cinemas. This trend in timewill increase as digital projection systems get better in quality andhigher in image resolution.

Another aspect of the conversion is to improve the quality of the audioportion of the immersive experience in a multiplex type theatre. Soundsystems for cinema have evolved over the decades and the trend continuesas an ongoing effort to attract the paying viewer. The surround soundsystems used in today's Multiplex theatres can provide a degree of“ambience” in the audio experience but these systems still lack theability to create realistic immersive audio.

From the time “talkies” were introduced, motion picture cinemas had“monaural” sound systems, having only one loudspeaker located behind thecenter of the screen. The sound experience in such a cinema was very onedimensional and flat, with no ability to simulate sounds coming fromdirections other than the center of the picture. In order to improve theaudio experience, cinema designers and equipment suppliers experimentedwith a variety of multiple loudspeaker (“multi-channel”) schemesdesigned to immerse the audience in a sound field which could add to the“suspension of disbelief” desired by filmmakers. One of the earliestattempts at multi-channel sound was the premier of Walt Disney's“Fantasia” in 1939. Disney experimented with a number of sound systemloudspeaker configurations as outlined in an article by William E.Garity and John N. A. Hawkins published in the August 1941 issue of thejournal of the SMPTE. The last two versions of the Fantasound system,known as Mark IX and X, used 5 loudspeakers and sound from 3 separatetracks. The loudspeakers were positioned such that 3 were behind thescreen (i.e. left, center, and right) and one loudspeaker was in eachrear corner. The two sets of rear corner loudspeakers were switched into supplement or replace the corresponding left and right frontloudspeakers at select times during the picture presentation.Unfortunately, the war and economics cut short Disney's sound systemexperiments. In the early 1950's, Cinerama brought multi-channel soundto the forefront again with 5 to 7 loudspeaker channels located aroundthe audience.

During the 1950's there were several theatres equipped for the playbackof multi-channel sound, of which there were primarily two formats bothusing magnetic stripes printed on the film. The CinemaScope 35 mm filmformat provided four discrete channels, consisting of 3 loudspeakersbehind the screen and a monaural surround channel provided by severalsmall loudspeakers located on the side and rear walls of the cinema.These surround loudspeakers provided a degree of “ambience” to the soundexperience in combination with the directional sound produced by the 3screen loudspeakers, and thus added to the immersive effects presentedto the audience. The Todd-AO 70 mm film format added two additionalloudspeakers behind the screen, Left Center and Right Center, betweenthe center loudspeaker and the left and right speakers.

In the 1970's, Dolby pioneered several advances in cinema sound,including extended low-frequency sound (sub-bass), noise reduction, andStereo Optical sound. Dolby Stereo Optical provided 4 channels of sound(left, center, right, and mono surround) using an encoding technique tostore the analog soundtrack on two analog optically printed stripes onthe film. This became the standard for normal cinemas, and remains inuse today in non-digital cinemas.

In 1979, Dolby added to the immersive effects of cinema sound bydeveloping stereo surrounds, in which the left distributed loudspeakerchannel could reproduce different sounds than the right channel. But,the surround effects were still effectively ambience sounds, and wereunable to reproduce directionality with any precision due to thedistributed configuration of the surround loudspeakers.

In the 1980's, IMAX® Corporation standardized on a 6-channel soundsystem with a discrete surround sound configuration and a separatesub-bass channel for IMAX® Theatres. This type of system providessubstantially better sound imaging by utilizing custom-designedloudspeakers located in each rear corner behind the audience, eachpowered by a separate audio channel. The immersive effects of this typesystem are much more impressive, and allow the filmmaker the ability toposition sound more precisely—directly in front of, in front above,around, and behind the audience.

In 1987, Imax installed the first Digital Sound Reproducer in an IMAXTheatre. By 1990, uncompressed Digital Sound was available to all IMAXTheatres. Also in 1990, with the release of the movie “Dick Tracy,” CDSuncompressed digital sound on 35 mm film was introduced to the generalcinema industry by a joint venture of Orcon and Kodak.

Because CDS was not compatible with standard optical sound on 35 mmfilm, the CDS format was discontinued soon thereafter.

Between 1992 and 1993, three systems of digital sound for cinema werereleased—Dolby Digital, DTS, and Sony SDDS. All three of these formatsutilized some form of digital compression to reduce the storagerequirements (on CD-ROM for DTS) or to allow the digital audio signal tobe printed on the 35 mm film (with Dolby Digital and SDDS) withoutdisplacing the optical track as did the CDS system. While these systemsuse different compression techniques—some considered “better sounding”than others—IMAX Digital Sound remains the only uncompressed digitalcinema sound format in general use today.

All three of the digital sound systems used in conventional 35 mm anddigital cinemas make use of the same distributed side and rear surroundloudspeakers to create a sense of ambience for the film soundtrack. Eventhough these digital systems may sound “better” than the older opticalsystems, sound immersion remains limited due to the inability ofmultiple distributed loudspeakers to provide precise directionality andimage placement.

Motion picture exhibitors have expressed interest in providingadditional quality improvements to mainstream motion pictures by addinga special, custom designed, smaller scale Imax theatre to theirmultiplexes. This has proved popular with patrons and exhibitors, buthas not been widely adopted because of high costs associated withconstructing the adjunct theatre.

It is desirable to be able to provide mainstream multiplex theatres withthe same manner of widescreen presentation experience as large hallcustom designed theatres, but at a lower, more affordable cost. There isa need to be able to economically convert an existing mainstreammultiplex motion picture theatre into a widescreen theatre that isqualitatively superior in terms of projected image quality, field ofview, and of a more realistic immersive audio experience that does notexist in multiplex type theatres. As a result of having overbuilt thenumber of multiplex theatres the economics of this situation dictatesthat converting existing multiplex theatres makes better sense thanbuilding additional new multiplexes with larger screen sizes. Thefollowing discussion of the inventive approach by the applicantaddresses this need.

SUMMARY OF THE INVENTION

The invention is a method of cost effectively converting an existingstandard motion picture theatre, such as the multiplex theatre that usesfilm/digital projection, to a highly immersive, large field of viewmotion picture theatre. Hereinafter the term “multiplex theatre” is usedin a more general sense to represent all motion picture theatres thatare: not the Grand Theatre hall sizes of the 1920s, not the theatricalstage theatres, and not the IMAX geometry theatre halls originally builtfor Imax presentations. The inventive method includes:

-   moving the motion picture screen closer to the audience to increase    the field of view; and-   employing projection means to improve the quality of images on the    screen such that the audience does not see unrealistic or    non-natural image artifacts which would occur by just simply    magnifying the existing projected image.

In some situations, carrying out the first step may inadvertently blockaccess to an existing emergency exit door necessitating an additionalstep of moving a portion of the screen to allow access to the emergencyexits.

To cost effectively convert a multiplex theatre sound system so that arealistic audio immersion experience is created may involve thefollowing:

-   changing the loudspeaker configuration to one that uses 5 discrete    loudspeakers with Proportional Point Source technology and one    sub-bass loudspeaker; and-   driving each loudspeaker from a separate sound channel; with-   the sound system using a 5.1 sound track that is mixed differently    than standard cinema 5.1 sound track and-   the sound system using uncompressed digital sound with a resolution    of 16 bits or greater.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a typical multiplex theatre.

FIG. 2 is an elevation view of a typical existing theatre.

FIG. 3 is a plan view of a multiplex theatre after conversion.

FIG. 4 is an elevation view of a multiplex theatre after conversion.

FIG. 5 is a plan view of a converted multiplex theatre illustrating anovel emergency exit access system.

FIG. 6 is an elevation view of a converted theatre illustrating a novelemergency exit access system.

FIG. 7 is a front view of the screen in a converted theatre illustratingthe novel emergency exit access system in a normal state.

FIG. 8 is a front view of the screen in a converted theatre illustratingthe novel emergency exit access system in an activated state.

FIGS. 9 a-9 b are a plan view of a converted theatre and a front view ofthe screen illustrating the position of the PPS speakers.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to FIG. 1, a plan view of a typical 35 mm film and/ordigital multiplex theatre is depicted at 1. Theatre 1 includes a frontprojection screen 2, motion picture projector 3, a theatre enclosurerear wall 4, a seating deck 5 upon which there are seats for spectators6. The distance d1 indicates the distance from the centre of screen 1 tothe inner surface of rear wall 4. The space between the screen and therear wall is occupied by a screen support structure (not shown) andsound system speakers (also not shown). Angle AOB represents thehorizontal field of view of the motion picture theatre as seen from alocation coincident with the point of projection, O. In the case of FIG.1, this angle equals approximately 45 degrees. This represents a minimumhorizontal field of view for patrons in the theatre; as one sits closerto the screen the horizontal field of view increases. A patron sittingat position X in FIG. 1, for example, would have a horizontal field ofview of 55 degrees, as is indicated by angle AXB. The widest possiblefield of view in a theatre such as depicted in FIG. 1 is indicated bythe angle AZB representing a patron sitting in a seat in the front row,and is equal to about 110 degrees. It must be noted however that in atypical multiplex cinema theatre the visual quality of images whenviewed from a close position, like point Z in FIG. 1 is not as good whenseated further back. In the close-up seats unnatural visual defects suchas insufficient image resolution, film grain, visible pixels, blurrededges, and image unsteadiness are more easily perceived. Generally,patrons in these theatres tend to sit further from the screen when giventhe opportunity where image defects are less apparent.

FIG. 2 illustrates an elevation view of multiplex cinema theatre 1. Itcan be seen that screen 2 is less than the full height of the theatrewith observable gaps above the upper edge of the screen and below thelower edge of the screen. These gaps would be covered up by darkcurtains or similar observant material to help conceal the limitedvertical extent of screen 2. Angle COD represents the minimum verticalfield of view in a theatre of this geometry and is equal to about 20degrees. As one moves closer to the screen, the vertical field of viewincreases, as one would expect. At position X the vertical field of viewis about 25 degrees while at position Z, it is about 50 degrees. It canbe seen that seating deck 5 is sloped at an angle of about 20 degrees inthe rear portion of the theatre and about 15 degrees in the sectioncloser to the screen. This slope, or rake, of seating deck 5 allows eachrow of seats to be located on a separate platform thereby giving patronsa clear vertical field of view of the entire screen.

The horizontal and vertical fields of view available to patrons in atypical multiplex theatre are significantly below the capabilities ofthe human visual system, which is estimated to have a recognizablehorizontal field of view of 120 degrees and a vertical field of view ofabout 70 degrees. The estimated perceptual field of view is about 200degrees horizontally and 135 degrees vertical.

Referring now to FIG. 3, the same multiplex cinema theatre is shownafter conversion to an improved, more visually immersive motion picturetheatre. Screen 2, shown in outline, has been removed and replaced by anew, larger screen 10 which is now located at a new distance, d2, fromrear wall 4. Screen 10 extends from wall to wall, and as shown in FIG.4, extends from floor to ceiling. The hatched area in the lower part ofseating deck 5 in FIG. 3 represents seats that have been removed toaccommodate the new screen and viewing geometry of the improved theatre.A new projector 7 replaces the standard multiplex cinema projector andis capable of projecting images with superior quality in terms ofresolution, sharpness and steadiness.

The minimum horizontal field of view of the improved theatre is nowabout 55 degrees, while the minimum vertical field of view is about 30degrees. At position X, the horizontal field of view is about 75 degreesand the vertical field of view is about 40 degrees. At position Z thehorizontal field of view is about 130 degrees and the vertical field ofview is about 80 degrees. To a viewer sitting at the seat closet to thescreen centre, the new screen position and size appears 115% larger thanthe conventional screen size. To the viewer sitting at the position X inthe theatre with the new screen position and size the screen sizeappears to have increased 100%. To the viewer sifting at the rear mostposition of the theatre with the new screen position and size the screensize appears to have increased 85%. The viewer in position X, when thescreen has been moved forward, experiences an increase in image angularFOV of about 35% horizontally and 60% vertically. The increase invertical FOV is especially significant and is an improvement that untilnow has been largely overlooked by the prior art traditional cinemasystem advances such as Cinerama which concentrated on expandinghorizontal FOV. The increased FOV, both vertical and horizontal, is animportant presentation improvement resulting from the inventive methodof theatre conversion.

It is possible to only increase the image fidelity of the projectionsystem such that the viewers see the same fidelity of image on theforward moved screen as when the screen was positioned prior to theconversion. This would mean that viewers in the first few front rowseats in the converted theatre would experience the same quality ofimage prior to the conversion that was already marginally low, hence,one reason viewers move further back in the theatre. The most evidentimage fidelity issues of front row viewing are lack of image resolution,the presence of film grain artifacts becoming apparent, or in the caseof digital projection, image pixels becoming apparent. Other factorsonly associated with conventional film projectors that specificallycontribute to image contrast MTF degradation are film transportunsteadiness and softening of film image due to heat pop of the film. Inthe theatre conversion front row seats have been removed, so there arefewer seats in the theatre. To give front row seats a more acceptableviewing experience the image projection fidelity can be furtherincreased so that the front row viewers now get the same or better imagequality as the viewers seated further back from the screen prior to theconversion.

In the preferred embodiment one type of projector that uses film with alarger image area and does not suffer from image unsteadiness or filmheat pop associated with conventional cinema film projection systems isthe rolling loop projection system.

The combination of improved image quality on the screen with increasedhorizontal and vertical fields of view significantly improves thesensation of visual immersion in the images. Applicant has confirmedthrough research studies in perception and cinema viewer's preferences,the improvement in the presentation of the converted theatre issignificantly better than the presentation in a standard multiplexcinema theatre.

In addition to significantly improving image quality and the enhancingthe feeling of immersion in 2D images, the wider fields of view providedby the inventive method of theatre conversion is necessary for properand realistic immersive experiences of 3D motion picture presentations.

In some multiplex theatre designs emergency exits are at the screen endof the theatre on the side wall. These exits could be blocked by the newposition of the screen in a converted theatre. This situation may not beacceptable by local safety regulations. The inventive conversion methodaddresses this possibility by inclusion of an emergency screen accesssystem consisting of a system door and means for automatic activation ofsaid door. FIGS. 5 through 8 illustrate one embodiment of such a system.

Referring now to FIGS. 5 and 6, an emergency exit door 21 which waslocated in front of original screen 2, shown in outline, is now locatedbehind new screen 10. Motion picture screen 10 consists of a perforated,pliable projection surface material such as vinyl which is supported andstretched by a frame (not shown) located behind the projection surface.FIG. 7 illustrates schematically how one corner of projection screen 10is not fastened rigidly to a supporting frame, but is held in place bythe magnetic attraction between metal rods 25 in the edges of screen 10and electromagnetic means 26 attached to the wall and floor of theconverted motion picture theatre. A cable 23 is attached to the rearcorner of the projection surface of screen 10. The other end of cable 23is attached to a counterweight 24 after first passing over a pulley 22attached to the rear wall surface 4. In an emergency situation, anautomatic activation means sends a signal to electromagnets 22 switchingthem off thereby removing the magnetic force which had been holding themetal rods firmly against the wall and floor of the theatre. The cornerof the projection surface of screen 10 is then pulled backwards andupwards by the counterweight as it falls by gravity towards the ground.FIG. 8 depicts the system door to the emergency exit in an activatedposition with the corner of screen 10 pulled upwards and backwards andcounterweight 24 resting on the ground. An illuminated sign is shown at27 directs patrons to the newly revealed emergency exit 21. Winchingmeans, not shown, is used to pull up the counterweight so that thesystem and screen can be reset after it has been activated.

The activation signal may be effected by a number of activation systems,separately or in parallel, including a mechanical swing gate crash barlocated at the bottom aisle stairs, pushing or applying pressure to thescreen surface, by a signal from the building emergency alarm system, amanual release button at the usher station, or by a patron activatedmotion, IR or touch pad sensor near the vicinity of the corner ofscreen.

In addition to the potential necessity of using the emergency screenaccess system there are other negative consequences associated with theinventive method of multiplex theatre conversion that must be remediedor accepted including the creation of a large sound cavity behind thenew screen assembly, and the necessity to remove a number of seats nearthe front of the theatre which are too close to the new screen foreffective viewing. The first problem is addressed by the provision of asound absorbing acoustic wall behind the new screen, that can be builtinexpensively because it need not be a load bearing structural wall. Ifthe sound barrier is forward of the theatre exit door an additional doorwould have to be built into the sound barrier. The second problem, seatremoval, and the loss of revenue associated with those seats, is notoverly detrimental to the success of the multiplex complex because ahigher admission price can be charged for the remaining seats. Inaddition, it is believed that the premium quality and unique immersiveexperience offered by the new motion picture will lead to a higher, andsustained, level of theatre occupancy over its operating lifetime.

The conversion of a 35 mm film and/or digital projection multiplextheatre is not limited to the steps outlined above but can includefurther steps such as: tilting the screen forward or backwards withrespect to the audience to increase the screen surface area in thevertical dimension or to compensate for keystoning or light reflectionback to the audience; curving the screen in the vertical direction toprovide a compound curved screen; or modifying the ceiling to provideadditional vertical height for the new screen.

The conversion is also not limited to improving the quality of thevisual experience but also converting the sound system to give asignificantly more realistic and immersive audio experience. A trulyimmersive audio environment, similar to what the audience experiences inan IMAX® Theatre, is one in which the sound system has the ability torealistically position sound images in front of, around, and behind theaudience. The converted sound system must be reasonably cost effectiveand at the same time create a realistic immersive audio experience forthe majority of seats in the theatre. A conversion that does this isdescribed below.

The theatre sound system is setup with a loudspeaker configuration asillustrated in FIGS. 9 a and 9 b. FIG. 9 a is a plan view of theloudspeaker positions in a converted theatre and FIG. 9 b is a frontview of the loudspeakers behind the screen in a converted theatre. Thereare 5 loudspeakers 101, 102, 103, 104, and 105, each driven from aseparate audio source, and each with appropriate amplification andequalization. There is a 6^(th) Sub-Bass Loudspeaker assembly 106consisting of several sub-woofer elements grouped together thatre-produce the low-frequency sound derived from the 5 audio channels.Powered with sufficient amplification these loudspeakers providerealistic sound levels for low-frequency sounds such as rocket launches,earthquakes, and explosions. Each audio channel is fed uncompresseddigital sound with a resolution of 16 bits or greater from the DigitalSound Reproducer. The Digital Sound Reproducer is normally positioned inthe sound rack 120 in the projection booth.

The loudspeaker positions in the theatre are referred to as: Left Rear101, Left Screen 102, Center Screen 103, Right Screen 104, Right Rear105 and the Sub Bass position 106. Loudspeakers 102, 103, and 104 in thefront are positioned between the newly installed sound barrier 110 andthe screen 10, part way between the screen base and top. Sub bass 106 islocated between the sound barrier 110 and the screen 10 under CenterScreen 103. The screen is perforated with tiny holes to let the soundthrough yet obscure speaker visibility. The complete sound system isdesigned to cover the entire audio spectrum and provide sufficient soundlevel within the theatre.

Loudspeakers 101, 102, 103, 104, and 105 are designed with ProportionalPoint Source (PPS) Technology. The principles of the physics used in PPSLoudspeaker technology is known to those skilled in the art. In generalterms PPS Loudspeaker technology refers to the ability of a loudspeakerto direct proportionately more sound energy to seats farther away thanthat directed to the closer seats from a single or virtually singlesource position. Hereinafter this will be referred to as “PPStechnology.” In order to achieve optimum sound dispersion, PPS typeloudspeakers must be designed for the specific theatre geometry. IMAX®Loudspeakers used in this conversion are designed with PPS Technology,using horns with asymmetrical dispersion patterns specifically designedto provide balanced sound distribution for multiplex cinemas having theappropriate geometry.

During installation each loudspeaker is placed, aimed, and aligned toposition the sound dispersion pattern for maximum immersive effect. Thealignment process involves use of computer aided design to determine theoptimum loudspeaker “pointing angle” for each of the 5 loudspeakers inthe theatre. Then, with the use of LASER alignment tools, theloudspeaker can be aimed to match the predetermined “pointing angle.” Acinema sound system using PPS technology properly configured andequalized to the accepted industry standard, allows all theatre patronsto perceive sound from all channels as having essentially the samevolume level and tonal quality. Thus, the sound “image” desired by thefilmmaker is reproduced for the entire audience area. Surround soundsystems that do not employ the use of PPS-type loudspeakers providebalanced sound, or a “sweet spot” for only a few seats—generally nearthe center of the theatre. Other patrons may hear only one or twoloudspeakers predominantly, with little contribution from the othersound channels.

There are three significantly differentiating aspects of the convertedsound system with respect to multiplex cinema sound systems. Not onlyhas this type of immersive surround sound system conversion not beendone before in multiplex theatres, there are differences that make theinvented sound system conversion process truly unique.

The first differentiating aspect is that the sound system, as shown inFIGS. 9 a-9 b, uses discrete loudspeakers in the rear corners of thetheatre with separate sound channels to provide the greater surroundsound imaging capability. All conventional surround systems used inmultiplex cinemas make use of distributed side and rear surroundloudspeakers to create a sense of ambience but these lack the ability toprovide precise sound directionality and sound image placement.

Secondly, in a sound system with 5 discrete PPS type loudspeakers andsound channels it becomes possible to place sound images in front of,around, and behind the audience. To optimize sound placement in a 5channel discrete source sound system the 5 sound tracks must be re-mixedin order to provide the audience with a truly more realistic immersiveaudio experience. Multiplex Cinemas have not configured their soundsystem setup in this way before.

The third aspect relates to the Digital Sound Reproducer. As previouslynoted, other multiplex cinema sound systems utilize either opticalanalog audio tracks printed on the film, or one of three digital soundformats—all of which compress the digital audio by significant amountsin order to fit the storage/playback media. The Digital Sound Reproducerwithin the converted theatre uses uncompressed digital sound with aresolution of 16 bits or greater to provide all the audio resolution anddynamic range intended by the filmmaker and the film sound engineer.

The IMAX multiplex theatre converted sound system with its uniqueDigital Sound Reproducer will provide very high quality digital audiosurpassing all other available cinema sound formats in fidelity,resolution, dynamic range and sound image placement capability. Theresult is sound unrivalled in achieving the goal of a realisticimmersive cinema experience, and the “suspension of disbelief” desiredby filmmakers.

The result of a multiplex theatre converted using some or all the stepsdescribed above creates for the audience a substantially improvedrealistic visual and audio immersion experience for 2D and 3D motionpicture presentations. To date, this type of conversion has not beendone before in multiplex theatres.

The foregoing is provided for purposes of illustrating, explaining, anddescribing exemplary embodiments and certain benefits of the presentinvention. Modifications and adaptations to the illustrated anddescribed embodiments will be apparent to those skilled in the relevantart and may be made without departing from the scope or spirit of theinvention.

1. A method of converting a multiplex theatre hall into an immersivemotion picture theatre hall, comprising: a. providing a multiplextheatre hall having a rear wall and comprising: i. a first projectionscreen positioned a distance D1 from the rear wall; ii. a set ofloudspeakers; and iii. at least first and second patron seat locations;b. providing a projection screen positioned a distance D2 from the rearwall, where D2 is greater than D1, by either (i) moving the firstprojection screen or (ii) erecting a second projection screen; c.providing a sound absorbing acoustic barrier positioned a distance D3from the rear wall, where D3 is less than D2; d. positioning at leastsome of the set of loudspeakers a distance D4 from the rear wall, whereD4 is greater than D3 and less than D2, such loudspeakers receivingsignals via separate audio channels; and e. aiming the set ofloudspeakers so that patrons sitting at the first and second seatlocations perceive sound from all audio channels as having essentiallythe same volume level and tonal quality, thereby creating an immersivemotion picture theatre hall.
 2. A method of converting a multiplextheatre hall into an immersive motion picture theatre hall according toclaim 1 in which:D3>D1.
 3. A method of converting a multiplex theatre hall into animmersive motion picture theatre hall according to claim 1 in which:D2−D3<D3−D1.
 4. A method according to claim 1 further comprising mixingdifferently a standard cinema 5.1 sound track so as to provide signalsto the set of loudspeakers.
 5. A method according to claim 1 in whichproviding a sound absorbing acoustic barrier comprises providing a soundabsorbing acoustic wall.